1. Field of the Invention
The present invention relates to a method for detecting a target biological material, and more specifically to a method for detecting a target biological material (e.g., DNA) using DNA barcodes by which a trace amount of the target biological material can be detected in a rapid and economical manner without performing polymerase chain reaction (PCR).
2. Description of the Related Art
A biochip or biosensor is designed so that various probes, such as DNA, antibodies, enzymes or cells, are immobilized on the surface of immobilization supports to allow an analyte of interest to specifically bind to the probes. Such a biochip or biosensor can be used to enable diagnosis of a disease using a small amount of a sample and to facilitate experiments, such as high throughput screening (HTS) and enzymatic activity measurement, on a large scale.
Many detection systems have been developed since the 1980's. Most of the early detection systems have a limitation in the amount of biological materials capable of being bound to immobilization supports and suffered from many difficulties in their commercialization because of expensive isotopes as main materials for analysis and problems in terms of safety. Since the early 1990's, many methods have been reported wherein fluorescent materials are used instead of isotopes and many kinds of biological materials can be immobilized in large amounts. Until now, remarkable progress has been made in the development of biochips and biosensors.
It is known that biochips and biosensors hitherto developed present the following drawbacks: 1) methods based on label-free analysis have the advantage of low cost but offer the problems of limited selectivity and low sensitivity; 2) labeling methods are disadvantageous because of increased cost; 3) there is the possibility of binding to materials other than analytes of interest in samples; and 4) when general analytical methods are employed for the analysis of DNA as an analyte of interest, a costly amplification technique (e.g., PCR amplification) is needed to increase the sensitivity of the analysis.
Numerous attempts to solve these problems have been made. For example, a new concept of amplification of signals using DNA barcodes was introduced by Mirkin, a professor at Northwestern University, USA. Based on this concept, trace amounts of samples at attomolar levels can currently be analyzed without performing PCR. However, Mirkin's technique requires the use of expensive materials (e.g., gold) and involves a complicated procedure associated with the formation of platforms. Several modifications to Mirkin's technique are being introduced.
According to several methods that have recently been introduced, gold nanoparticles (NRs) binding to two types of short DNA and magnetic particles (MMPs) binding to one type of DNA are mainly used and amplified DNA signals are analyzed by a chip-based-detection method. Analytical results of the methods obtained prostate specific antigen (PSA) demonstrate that the antigen can be analyzed at attomolar levels (1018 M). However, currently used methods also necessitate the use of nanoparticles and gold particles. Under these circumstances, continuous efforts are being made towards cost reduction and simplification of the analytical procedure.